A systematic review of comparisons of effect sizes derived from randomised and non-randomised studies

BACKGROUND

There is controversy about the value of evidence about the effectiveness of healthcare interventions from non-randomised study designs. Advocates for quasi-experimental and observational (QEO) studies argue that evidence from randomised controlled trials (RCTs) is often difficult or impossible to obtain, or is inadequate to answer the question of interest. Advocates for RCTs point out that QEO studies are more susceptible to bias and refer to published comparisons that suggest QEO estimates tend to find a greater benefit than RCT estimates. However, comparisons from the literature are often cited selectively, may be unsystematic and may have failed to distinguish between different explanations for any discrepancies observed.

OBJECTIVES

The aim was to investigate the association between methodological quality and the magnitude of estimates of effectiveness by comparing systematically estimates of effectiveness derived from RCTs and QEO studies. Quantifying any such association should help healthcare decision-makers to judge the strength of evidence from non-randomised studies. Two strategies were used to minimise the influence of differences in external validity between RCTs and QEO studies: a comparison of the RCT and QEO study estimates of effectiveness of any intervention, where both estimates were reported in a single paper a comparison of the RCT and QEO study estimates of effectiveness for specified interventions, where the estimates were reported in different papers. The authors also sought to identify study designs that have been proposed to address one or more of the problems often found with conventional RCTs.

METHODS

DATA SOURCES

Relevant literature was identified from: The Cochrane Library, MEDLINE, EMBASE, DARE, and the Science Citation Index. References of relevant papers already identified experts. Electronic searches were very difficult to design and yielded few papers for the first strategy and when identifying study designs. CHOICE OF INTERVENTIONS TO REVIEW FOR STRATEGIES 1 AND 2: For strategy 1, any intervention was eligible. For strategy 2, interventions for which the population, intervention and outcome investigated were anticipated to be homogeneous across studies were selected for review: Mammographic screening (MSBC) of women to reduce mortality from breast cancer. Folic acid supplementation (FAS) to prevent neural tube defects in women trying to conceive. DATA EXTRACTION AND QUALITY ASSESSMENT: Data were extracted by the first author and checked by the second author. Disagreements were negotiated with reference to the paper concerned. For strategy 1, study quality was scored using a checklist to assess whether the RCT and QEO study estimates were derived from the same populations, whether the assessment of outcomes was 'blinded', and the extent to which the QEO study estimate took account of possible confounding. For strategy 2, a more detailed instrument was used to assess study quality on four dimensions: the quality of reporting, the generalisability of the results, and the extent to which estimates of effectiveness may have been subject to bias or confounding. All quality assessments were carried out by three people. DATA SYNTHESIS AND ANALYSIS: For strategy 1, pairs of comparisons between RCT and QEO study estimates were classified as high or low quality. Seven indices of the size of discrepancies between estimates of effect size and outcome frequency were calculated, where possible, for each comparison. Distributions of the size and direction of discrepancies were compared for high- and low-quality comparisons. FOR STRATEGY 2, THREE ANALYSES WERE CARRIED OUT: Attributes of the instrument were described by k statistics, percentage agreement, and Cronbach's a values. Regression analyses were used to investigate -variations in study quality. (ABSTRACT TRUNCATED)

Some ventilatory effects of propofol as sole anaesthetic agent

Ventilatory effects of propofol, used as a sole agent for the induction and maintenance of general anaesthesia, were studied in 14 healthy unpremedicated patients. Subarachnoid anaesthesia was established before induction of general anaesthesia. Induction was with propofol 2.5 mg kg-1 given while the patients breathed 100% oxygen. We intended to start an infusion of propofol 100 micrograms kg-1 min-1; maintain it for at least 25 min; make a first set of quasi-steady-state observations; double the infusion; and repeat observations after 25 min. The single induction bolus plus single rate infusion was not totally satisfactory: further boluses were usually needed. At induction there was apnoea in all but three patients, sometimes lasting more than 3 min; hyperventilation before induction, combined with hyperoxia, probably exaggerated this. Established ventilatory rates were generally 30% higher than awake. One patient became bradypnoeic. Tidal volume and minute ventilation, and the Tl:Ttot ratio, were reduced. Doubling the infusion rate had no clear effect on frequency or tidal volume, but it further reduced the Tl:Ttot ratio and caused an increase in PE'CO2 of 1 kPa. The ventilatory response to carbon dioxide was 58% of baseline awake control (95% confidence limits +/- 26%) at the lower infusion rate, with further slight depression when the infusion rate was doubled. Doubling the rate of infusion of propofol did not give twice the effect on ventilation, and probably is not giving twice the "depth" of anaesthesia. We cannot say if this is for pharmacokinetic or pharmacodynamic reasons.

What strategies can be used to effectively reduce the risk of concussion in sport? A systematic review

AIM OR OBJECTIVE

To examine the effectiveness of concussion prevention strategies in reducing concussion risk in sport.

DESIGN

Systematic review according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines.

DATA SOURCES

Eleven electronic databases searched and hand-search of references from selected studies.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

The following were the study inclusion criteria: (1) contained original human research data; (2) investigated an outcome of concussion or head impact; (3) evaluated a concussion prevention intervention; (4) included sport participants; (5) analytical study designand (6) peer-reviewed. The following were the exclusion criteria: (1) review articles, case series or case studies and (2) not in English.

RESULTS

The studies selected (n=48) provided evidence related to protective gear (helmets, headgear, mouthguards) (n=25), policy and rule changes (n=13) and other interventions (training, education, facilities) (n=10). Meta-analyses demonstrate a combined effect of a 70% reduction (incidence rate ratio (IRR)=0.3 (95% CI: 0.22 to 0.41)) in concussion risk in youth ice hockey leagues where policy disallows body checking, and the point estimate (IRR=0.8 (95% CI: 0.6 to 1.1)) suggests a protective effect of mouthguards in contact and collision sport (basketball, ice hockey, rugby).

SUMMARY/CONCLUSIONS

Highlights include a protective effect of helmets in skiing/snowboarding and the effectiveness of policy eliminating body checking in youth ice hockey. Future research should examine mouthguards in contact sport, football helmet padding, helmet fit in collision sport, policy limiting contact practice in youth football, rule enforcement to reduce head contact in ice hockey and soccer, ice surface size and board/glass flexibility in ice hockey and training strategies targeting intrinsic risk factors (eg, visual training).

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 2016:CRD42016039162.

The effects of cardiopulmonary bypass temperature on neuropsychologic outcome after coronary artery operations: a prospective randomized trial

The effect of systemic perfusion temperature on postoperative cognitive function was investigated in 96 adult patients undergoing elective coronary revascularization with cardiopulmonary bypass at 28 degrees C, 32 degrees C, or 37 degrees C. Neuropsychologic performance was assessed 1 day before the operation and 6 weeks after the operation. Five tests were adapted from the Wechsler Adult Intelligence Scale and two from the Wechsler Memory Scale.

RESULTS

No patients had major neurologic complications. Ninety-three patients completed the five Wechsler Adult Intelligence Scale tests, but only 70 went on to complete the Wechsler Memory Scale tests as well. In these, there was an effect of cardiopulmonary bypass temperature on the number of neuropsychologic tests in which there was a preoperative to postoperative deterioration (p = 0.021), the number with bypass at 37 degrees C being significantly greater than the number with bypass at 32 degrees C (p = 0.015). Subsidiary analyses using a multivariate linear model examined the effect of cardiopulmonary bypass temperature on the magnitude of change, with or without allowing for other possible confounding influences. There was an adverse effect of normothermic (37 degrees C) versus moderately hypothermic (32 degrees C) perfusion---more convincingly displayed in the analyses of all seven scores rather than just the Wechsler Adult Intelligence Scale scores. Further cooling to 28 degrees C conferred no additional benefit in terms of cognitive function. The importance of the deterioration is open to question.

Timing of translation in cross-language qualitative research

Although there is increased understanding of language barriers in cross-language studies, the point at which language transformation processes are applied in research is inconsistently reported, or treated as a minor issue. Differences in translation timeframes raise methodological issues related to the material to be translated, as well as for the process of data analysis and interpretation. In this article we address methodological issues related to the timing of translation from Portuguese to English in two international cross-language collaborative research studies involving researchers from Brazil, Canada, and the United States. One study entailed late-phase translation of a research report, whereas the other study involved early phase translation of interview data. The timing of translation in interaction with the object of translation should be considered, in addition to the language, cultural, subject matter, and methodological competencies of research team members.

The Effect of the "Zero Tolerance for Head Contact" Rule Change on the Risk of Concussions in Youth Ice Hockey Players

BACKGROUND

Ice hockey is a popular winter sport in Canada. Concussions account for the greatest proportion of all injuries in youth ice hockey. In 2011, a policy change enforcing "zero tolerance for head contact" was implemented in all leagues in Canada.

PURPOSE

To determine if the risk of game-related concussions and more severe concussions (ie, resulting in >10 days of time loss) and the mechanisms of a concussion differed for Pee Wee class (ages 11-12 years) and Bantam class (ages 13-14 years) players after the 2011 "zero tolerance for head contact" policy change compared with players in similar divisions before the policy change.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The retrospective cohort included Pee Wee (most elite 70%, 2007-2008; n = 891) and Bantam (most elite 30%, 2008-2009; n = 378) players before the rule change and Pee Wee (2011-2012; n = 588) and Bantam (2011-2012; n = 242) players in the same levels of play after the policy change. Suspected concussions were identified by a team designate and referred to a sport medicine physician for diagnosis. Incidence rate ratios (IRRs) were estimated based on multiple Poisson regression analysis, controlling for clustering by team and other important covariates and offset by game-exposure hours. Incidence rates based on the mechanisms of a concussion were estimated based on univariate Poisson regression analysis.

RESULTS

The risk of game-related concussions increased after the head contact rule in Pee Wee (IRR, 1.85; 95% CI, 1.20-2.86) and Bantam (IRR, 2.48; 95% CI, 1.17-5.24) players. The risk of more severe concussions increased after the head contact rule in Pee Wee (IRR, 4.12; 95% CI, 2.00-8.50) and Bantam (IRR, 7.91; 95% CI, 3.13-19.94) players. The rates of concussions due to body checking and direct head contact increased after the rule change.

CONCLUSION

The "zero tolerance for head contact" policy change did not reduce the risk of game-related concussions in Pee Wee or Bantam class ice hockey players. Increased concussion awareness and education after the policy change may have contributed to the increased risk of concussions found after the policy change.

The Impact of COVID-19 on High School Student-Athlete Experiences with Physical Activity, Mental Health, and Social Connection

COVID-19 restrictions led to reduced levels of physical activity, increased screen usage, and declines in mental health in youth; however, in-depth understandings of the experiences of high school student-athletes have yet to be explored. To describe the experiences of the COVID-19 pandemic on student-athletes' physical activity, social connection, and mental health, 20 high school student-athletes living in Calgary, Alberta participated in semi-structured interviews, designed using phenomenography. Participants reported variations in physical activity, social connections, and mental health which were influenced by stay-at-home restrictions and weather. Access to resources, changes to routines, online classes, and social support all influenced engagement in physical activity. School and sports provided opportunities for in-person social connections, impacted by the onset of the pandemic. Participants reported their mental health was influenced by social connections, online classes, and physical activity. Findings from this study will inform the development of resources for high school student-athletes amidst COVID-19.

Disturbed mother-infant interaction in association with congenital heart disease

OBJECTIVE

To investigate whether difficulties are experienced in the interaction between infants with congenital heart disease and their mothers and to identify infants who show compromised emotional development, in order to offer intervention during the early stages of postoperative compensatory growth.

METHODS

20 infants and their mothers were compared with 20 non-cardiac mother-infant pairs. Infants were filmed in interaction for 30 minutes two days before and six months after corrective surgery. Fifteen minutes of film were analysed in 180 5-s units. The emotional tone (affect) and the interpersonal engagement were classified as positive or negative by prespecified criteria. The percentages of positive scores were analysed. The mental health of the mothers was also assessed.

RESULTS

Cardiac infants showed less positive affect and engagement than the noncardiac group at both sessions. There was no correlation between of positive affect or engagement and the severity of the condition in either group. Cardiac mothers showed less positive affect and engagement than the comparison group, and were psychologically distressed at both sessions. The engagement scores of the mothers of the cardiac infants were also more variable.

CONCLUSIONS

Cardiac infants and their mothers have lower levels of positive affect and engagement than non-cardiac mother-infant pairs. Thus some mothers are unable to adapt to their infant. This leads to disordered interaction which is maintained at six months. This information can be used to offer intervention during the early stages of postoperative compensatory growth.

Broccoli sprout supplementation during pregnancy prevents brain injury in the newborn rat following placental insufficiency

Chronic placental insufficiency and subsequent intrauterine growth restriction (IUGR) increase the risk of hypoxic-ischemic encephalopathy in the newborn by 40 fold. The latter, in turn, increases the risk of cerebral palsy and developmental disabilities. This study seeks to determine the effectiveness of broccoli sprouts (BrSp), a rich source of the isothiocyanate sulforaphane, as a neuroprotectant in a rat model of chronic placental insufficiency and IUGR. Placental insufficiency and IUGR was induced by bilateral uterine artery ligation (BUAL) on day E20 of gestation. Dams were fed standard chow or chow supplemented with 200mg of dried BrSp from E15 - postnatal day 14 (PD14). Controls received Sham surgery and the same dietary regime. Pups underwent neurologic reflex testing and open field testing, following which they were euthanized and their brains frozen for neuropathologic assessment. Compared to Sham, IUGR pups were delayed in attaining early reflexes and performed worse in the open field, both of which were significantly improved by maternal supplementation of BrSp (p<0.05). Neuropathology revealed diminished white matter, ventricular dilation, astrogliosis and reduction in hippocampal neurons in IUGR animals compared to Sham, whereas broccoli sprout supplementation improved outcome in all histological assessments (p<0.05). Maternal dietary supplementation with BrSp prevented the detrimental neurocognitive and neuropathologic effects of chronic intrauterine ischemia. These findings suggest a novel approach for prevention of cerebral palsy and/or developmental disabilities associated with placental insufficiency.

Gas exchange in a three-compartment lung model analyzed by forcing sinusoids of N2O

A mathematical gas exchange model, using sinusoidal forcing functions of inert inspired gas (A. Zwart, R. C. Seagrave, and A. Van Dieren. J. Appl. Physiol. 41: 419-424, 1976), has been extended by us to include dead space (VD), a single alveolar compartment (VA) perfused with blood flow (Qp), and a shunt (Qs). In this new work we use N2O as the indicator gas in the mathematical model and in the experimental studies, in low enough concentrations [<6% (vol/vol)] to avoid anesthetic effects. Mathematical relationships between the inspired and expired N2O gas partial pressures, the blood gas N2O partial pressures, and their variation with forcing frequency are derived for a continuous ventilation uptake and a conventional anesthetic gas distribution model. We show that these gas and blood gas N2O relationships give direct derivation of cardiorespiratory parameters such as VA, Qp, the dead space-to-total ventilation ratio (VD/VT), and the shunt-to-total blood flow ratio (Qs/QT) without altering the subject's oxygenation and that they are essentially free from recirculation effects at high forcing frequencies > or = 2 min-1. Theoretical results from the model are presented for a wide range of forcing frequencies between 2 x 10(-2) and 10 min-1 (sinusoid periods 30-0.1 min), and these show that VA, Qp, and VD/VT can all be measured by N2O forcing frequencies > or = 1 min-1. We also present results from five animal studies, with an experimental inspired gas forcing frequency range of 0.125 to 2 min-1, which show qualitative agreement with the predictions of the continuous ventilation model. During these animal studies both mass spectrometric N2O respiratory gas measurements and intravascular polarographic arterial and mixed venous blood N2O partial pressure measurements were made, and examples of these in vivo measurements are presented, together with examples of the calculations derived from them.

Venous pressure and arm volume changes during simulated Bier's block

In investigating the possible causes of an observed complication of intravenous regional anaesthesia, cubital fossa venous pressures were measured distal to an inflated tourniquet as standard 40 ml volumes of normal saline were injected. The maximal pressures obtainable were limited by tourniquet pressure since the veins compressed under the tourniquet acted as 'Starling' spillover resistors. Once the compressing pressures were reached, with continued injection, fluid passed easily into the systemic circulation with little further increase in venous pressure. The rates of rise and maximum values of venous pressures tended to be increased by increased injection rates, and by failure to exsanguinate the arm, but the choice of injection site was paramount. Compared with more distal injections, cubital fossa venous injections are more likely to lead to leakage under the tourniquet and should never be used for intravenous regional anaesthesia.

Effects of cardiopulmonary bypass temperature on pulmonary gas exchange after coronary artery operations

BACKGROUND

Pulmonary dysfunction is one aspect of the postoperative morbidity associated with cardiopulmonary bypass. Normothermic systemic perfusion can result in shorter intubation times, which have been attributed to improved pulmonary gas exchange, but the influence of perfusion temperature on pulmonary gas exchange itself is not known.

METHODS

Pulmonary gas exchange was assessed using alveolar-arterial oxygen pressure gradients in 45 patients undergoing routine coronary revascularization who were randomized to undergo cardiopulmonary bypass at 28 degrees C, 32 degrees C, or 37 degrees C. This was part of a more comprehensive study of the effects of temperature on bodily systems. The gradients were estimated preoperatively with the patients breathing air, again over a period between 2 and 4 hours postoperatively during mechanical ventilation with three different oxygen concentrations (30%, 40%, and 60%), and again 1 hour after extubation while breathing the same three oxygen concentrations.

RESULTS

Preoperative alveolar-arterial oxygen pressure gradients on air were 24.4 +/- 8.2 mm Hg (mean +/- standard deviation) (28 degrees C), 24.5 +/- 20.4 mm Hg (32 degrees C), and 20.5 +/- 9.5 mm Hg (37 degrees C). Postoperatively, during ventilation and after rewarming, the gradients increased with the increase in inspired oxygen fraction concentrations (30% to 60%) from 67.1 +/- 12.0 mm Hg to 193.1 +/- 30.5 mm Hg (28 degrees C), from 76.4 +/- 20.6 mm Hg to 246.7 +/- 47.7 mm Hg (32 degrees C), and from 79.0 +/- 18.0 mm Hg to 222.9 +/- 40.5 mm Hg (37 degrees C), respectively. A similar pattern was noted 1 hour after extubation, when the gradients increased from 72.4 +/- 12.5 mm Hg to 256.6 +/- 26.5 mm Hg (28 degrees C), from 75.7 +/- 13.9 mm Hg to 252.7 +/- 38.3 mm Hg (32 degrees C), and from 69.1 +/- 19.3 mm Hg to 253.1 +/- 33.0 mm Hg (37 degrees C). There were no significant differences in alveolar-arterial oxygen pressure gradient between the three groups during ventilation or after extubation.

CONCLUSIONS

Cardiopulmonary bypass perfusion temperature does not influence alveolar-arterial oxygen pressure gradients in the first 12 hours after routine coronary artery bypass grafting in patients with uncompromised pulmonary and left ventricular function.

Pressures on endotracheal tube cuffs

The general relationships between the pressure inside an endotracheal tube cuff, the pressure exerted by that cuff on the tracheal wall and the airway pressure have been re-examined in a model system. In relatively recent literature, the tracheal wall pressure at a given cuff volume has been calculated as the difference between intracuff pressures at that volume when the cuff is inflated inside the trachea and when it is inflated whilst suspended freely in air. This has been used as a general relationship, as an alternative to direct measurement in real and model tracheas. In this study, the directly measured pressure was not generally equal to the pressure as calculated above.

Sport participation and injury rates in high school students: A Canadian survey of 2029 adolescents

INTRODUCTION

The objective of this study is to examine sport and recreational (S&R) activity participation and injury rates (IR) in high school students (ages 14-19).

METHODS

High school students (N = 24 schools, n = 2,029; 958 male, 1,048 female, 23 identified 'other' or missing; ages 14-19) in Alberta completed a web-based survey during class (October 2018-March 2019). Students identified their top three sports for participation in the past year. Primary outcome measures included IR for (a) any S&R-related injury, (b) most serious S&R-related injury resulting in medical attention, and (c) most serious injury resulting in restriction from S&R for at least one day.

RESULTS

In total, 1763/2029 (86.89%) respondents [861/958 (89.87%) male, 886/1048 (84.54%) female, 16/23 (69.57%) identifying as 'other' or missing] participated in an S&R activity in the past year. Top sports for male participation were basketball (33.08%; 95% CI 27.67-39.00), ice hockey (20.46%; 95% CI 14.87-27.47), and soccer (19.42%; 95% CI 15.67-23.80). Top sports for female participation were dance (22.52%; 95% CI 17.98-27.82), basketball (18.32%; 95% CI 14.32-23.14), and badminton (17.84%; 95% CI 13.35-23.43). Of the 1,971 students completing the S&R injury question, 889 reported at least one injury during the past year [(IR = 45.10 injuries/100 students/year (95% CI 39.72-50.61)]. The medical attention IR was 29.09 injuries/100 students/year (95% CI 24.49-34.17) and time loss IR was 36.00 injuries/100 students/year (95% CI 30.47-41.93).

CONCLUSIONS

High school student S&R IRs are high with 29% of adolescents reporting at least one medical attention injury within the past year. Injury prevention strategies targeting youth are necessary. Practical Application: Participation in S&R activities has multiple physical, psychological, and health benefits for adolescents, but some S&R activities also have greater risks of injury. This study informs the next sports to target for implementation of optimal prospective surveillance and injury prevention strategies among high school aged students.

Lysine and ornithine analogues of methotrexate as inhibitors of dihydrofolate reductase

The ornithine (6a) and lysine (6b) analogues of methotrexate (1) have been synthesized via condensation of 4-amino-4-deoxy-N10-methylpteroic acid (2) with N gamma-carbobenzoxy-L-ornithine tert-butyl ester (3a) and N epsilon-carbobenzoxy-L-lysine tert-butyl ester (3b), respectively. Removal of the protecting groups gave 5a and 6b. Compounds 6a and 6b and their precursor Cbz acids (5a and 5b) show significant inhibition of dihydrofolate reductase.

Assessment of cardiorespiratory function using oscillating inert gas forcing signals

A theoretical model (Hahn et al. J. Appl. Physiol. 75: 1863-1876, 1993) predicts that the amplitudes of the argon and nitrous oxide inspired, end-expired, and mixed expired sinusoids at forcing periods in the range of 2-3 min (frequency 0.3-0.5 min-1) can be used directly to measure airway dead space, lung alveolar volume, and pulmonary blood flow. We tested the ability of this procedure to measure these parameters continuously by feeding monosinusoidal argon and nitrous oxide forcing signals (6 +/- 4% vol/vol) into the inspired airstream of nine anesthetized ventilated dogs. Close agreement was found between single-breath and sinusoid airway dead space measurements (mean difference 15 +/- 6%, 95% confidence limit), N2 washout and sinusoid alveolar volume (mean difference 4 +/- 6%, 95% confidence limit), and thermal dilution and sinusoid pulmonary blood flow (mean difference 12 +/- 11%, 95% confidence limit). The application of 1 kPa positive end-expiratory pressure increased airway dead space by 12% and alveolar volume from 0.8 to 1.1 liters but did not alter pulmonary blood flow, as measured by both the sinusoid and comparator techniques. Our findings show that the noninvasive sinusoid technique can be used to measure cardiorespiratory lung function and allows changes in function to be resolved in 2 min.

Difficulties with positioning Robertshaw double lumen tubes

Difficulties in positioning Robertshaw tubes have been reviewed in a retrospective and a prospective series. Pre-operative cheat X-rays did not help in predicting difficulties. The performance of the Robertshaw tube was carefully recorded for each malposition in the prospective series, and the relationship of the malplaced tube to the tracheobronchial tree was reconstructed. This exercise allowed a more precise definition of the dangers of malpositions and formulation of procedure to minimize their incidence.

Baseline Performance of High School Rugby Players on the Sport Concussion Assessment Tool 5

CONTEXT

Version 5 of the Sport Concussion Assessment Tool (SCAT5) was released in 2017 with an additional 10-word list option in the memory section and additional instructions for completing the symptom scale.

OBJECTIVE

To provide reference scores for high school rugby union players on the SCAT5, including immediate memory using the 10-word list, and examine how age, sex, and concussion history affected performance.

DESIGN

Cross-sectional study.

SETTING

Calgary, Alberta high schools.

PATIENTS OR OTHER PARTICIPANTS

High school rugby union players (ages 15-18 years) participating in a 2018 season cohort study (n = 380, males = 210, females = 170).

MAIN OUTCOME MEASURE(S)

Sport Concussion Assessment Tool 5 scores, including total number of symptoms (of 20), symptom severity (of 132), 10-word immediate memory (of 30), delayed memory (of 10), modified Standardized Assessment of Concussion (of 50), and balance examination (of 30).

RESULTS

The median number of symptoms reported at baseline ranged from 5 to 8 across sex and age stratifications. Median symptom severity was lowest in males with no concussion history (7; range, 0-28) and highest in females with a concussion history (13, range = 0-45). Median total scores on immediate memory were 2-3 (range = 0-4) for males and 21 (range = 9-29) for females. Median total scores were 3 (range = 0-4) on digits backward and 7 (range = 0-20) on delayed memory (all groups). Based on simultaneous quantile (q) regression at 0.50 and 0.75, adjusted for age and concussion history, being female was associated with a higher total symptoms score (q0.75 β_female = 2.85; 99% confidence interval [CI] = 0.33, 5.37), higher total symptom severity score (q0.75 β_female = 8.00; 99% CI = 2.83, 13.17), and lower number of errors on the balance examination (q0.75 β_female = -3.00; 99% CI = -4.85, -1.15). Age and concussion history were not associated with any summary measures.

CONCLUSIONS

The 10-word list option in the memory section reduced the likelihood of a ceiling effect. A player's sex may be an important consideration when interpreting the SCAT5 after concussion.